A modern automobile has numerous electronic control units (ECUs) configured to control various vehicle subsystems, such as the engine, transmission, airbags, antilock braking, cruise control, electric power steering, audio systems, windows, doors and mirror adjustments, to name but a few. Some of these subsystems are independent, while others need to exchange data among themselves during the normal operation of the vehicle. When an ECU fails or is operational but faulty, the vehicle may exhibit poor performance or be completely disabled.
An ECU onboard a vehicle may suffer from a ground offset condition. A ground offset means that an expected reference voltage (e.g., zero volts) of an ECU has shifted. Thus, if the same signal voltage is measured relative to different reference voltages, then different measured values will be obtained. In an ideal network of ECUs, all of the reference voltages are identical such that all signal voltage measurements are consistent relative to one another. Ground offsets in vehicle ECUs can result in inconsistent vehicle operation, due to changing electrical loading. Moreover, ground offsets tend to worsen over time (perhaps rendering the stricken ECU inoperable).
Accordingly, it is desirable to have an onboard system and/or a diagnostic tool that can check the ground integrity of the ECUs onboard a host vehicle. In addition, it is desirable to have an efficient and automated methodology for identifying and locating the source of a ground offset in a network of ECUs. Furthermore, other desirable features and characteristics will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the foregoing technical field and background.